This invention relates to pipe couplings of the type formed of a pair of semicircular segments which are bolted together to form a circular casing that extends around and couples together adjacent pipe ends. An example of that type of coupling is illustrated in U.S. Pat. No. 3,054,629 issued Sept. 18, 1962 to Piatek.
Prior couplings of the type formed of a pair of semicircular segments are usually made of metal castings. Each of the segments is formed with exterior, diametrically extending lugs. When the segments are arranged together, the lugs overlap. Bolts are extended through the lugs for fastening the segments together and producing the circular shape of the casing.
In the past, the casings have been formed either U-shaped in cross-section or in solid cross-sections. Where they have been U-shaped in cross-section, their legs were designed for fitting into grooves formed on the exterior surfaces of the adjacent pipes so that the pipes are interlocked together with the casing. In the instances where the couplings have been more solid in cross-sectional shape, they have been fastened to the pipes by other means. However, in either event, the casing segments have included lugs which are arranged to overlap and to be bolted together.
Because couplings of the type described above are intended for use in coupling together a wide variety of different diameter pipes, it has been necessary to stock a large number of different size segments. Since it is common to form the segments of castings, it has been necessary to form expensive patterns and, in many cases, expensive molds for use, when necessary, to produce new segments. These molds and patterns have been relatively expensive to manufacture and to inventory until needed.
In addition, the casting of the lugs requires additional care and results in additional imperfections in the castings from time to time which increases the amount of scrap in the production of these kinds of couplings.
Further, where the coupling segments are formed with lugs, their sizes and weights are materially increased so that transporting them, stocking them in inventory, and carrying them to plumbing sites where they are to be used is relatively awkward and costly.
Hence, this invention relates to an improved coupling in which the conventional lugs are eliminated and, instead, a small number of "standard" fasteners, which are separate from the coupling castings, may be used for fastening together a large number of different size segments. Thus, the segments are smaller, less costly to manufacture and to transport, and are simpler to stock and handle since a wide assortment of sizes of semicircular segments may be used with a considerably smaller number of sizes of fasteners.